Permanent Collection Objects

Juneau—Douglas City Museum

2003.57.044 A—N

2003.57

Donated by the U.S. Bureau of Land Management.

Sample, Mineral

Large Round Epoxy Disks with Polished Rock Chips

1970

Black Bakelite rings filled with epoxy resin and rock chips. Rock chips highly polished (except M and N). Engraved marking on back (except M and N). Small circular indents on side of rings. .75 inches by 1.5 inches by 1.5 inches except A and N are .75 inches by 1.25 inches by 1.25 inches.
A — "654 5 / xxa". Massive sulfide. Primarily copper minerals.
B — "502B". Massive and disseminated copper and iron sulfides in quartz.
C — "504a" Massive iron and copper sulfides in quartz.
D — "B—2—1a" Massive sulfide. Note layering. Probably copper, iron, and lead sulfides. Yellow is chaliopyrite (not gold!).
E — "504" Sulfides in quartz vein.
F — "504b" Iron and copper sulfides in quartz.
G — "526x" Disseminated sulfides in quartz.
H — 525xa". Disseminated copper and zinc(?) sulfides in quartz.
I — "500". Disseminated pyrite (note cubic shapes) in quartz and feldspar matrix.
J — "502c" Disseminated pyrite and galena(?) in quartz matrix.
K — 502D". Nearly massive iron, lead, zinc, sulfides in quartz matrix.
L — 522 x B". Massive sulfides. Primarily iron and copper.
M — "B—2—1—b" on white adhesive label. Massive sulfide chip. Not polished.
N — "65038F" on white adhesive label. Granitic rock chip. Not polished.

Used by U.S. Bureau of Mines for mineral resource evaluation and analysis. Specimens made and petrographic analysis performed in petrographic laboratory in Juneau by Walter Gragy & Mary Ann Parke, both geologists.
Two unfinished specimens ("M" and "N") show specimens prior to the high polishing necessary to use reflected light or ore microscopy to identity and analyze opaque minerals. Small circular indentations are from clamps on the "Vibromat", machine used to acquire high polish.

History
Government
Federal
Geological
T&E
Mining